The present invention relates to systems and methods for positioning guidewires in a body lumen, and to catheter systems for delivering stents.
A type of endoprosthesis device, commonly referred to as a stent, may be placed or implanted within a vein, artery or other tubular body organ for treating occlusions, stenoses, or aneurysms of a vessel by reinforcing the wall of the vessel or by expanding the vessel. Stents have been used to treat dissections in blood vessel walls caused by balloon angioplasty of the coronary arteries as well as peripheral arteries and to improve angioplasty results by preventing elastic recoil and remodeling of the vessel wall. Two randomized multicenter trials have recently shown a lower restenosis rate in stent treated coronary arteries compared with balloon angioplasty alone (Serruys, P W et al., New England Journal of Medicine 331: 489-495 (1994) and Fischman, D L et al. New England Journal of Medicine 331:496-501 (1994)). Stents have been successfully implanted in the urinary tract, the bile duct, the esophagus and the tracheo-bronchial tree to reinforce those body organs, as well as implanted into the neurovascular, peripheral vascular, coronary, cardiac, and renal systems, among others. The term xe2x80x9cstentxe2x80x9d as used in this Application is a device which is intraluminally implanted within bodily vessels to reinforce collapsing, dissected, partially occluded, weakened, diseased or abnormally dilated or small segments of a vessel wall.
One of the drawbacks of conventional stents is that they are generally produced in a straight tubular configuration. The use of such stents to treat diseased vessels at or near a bifurcation (branch point) of a vessel may create a risk of compromising the degree of patency of the main vessel and/or its branches, or the bifurcation point and also limits the ability to insert a branch stent into the side branch if the result of treatment of the main, or main, vessel is suboptimal. Suboptimal results may occur as a result of several mechanisms, such as displacing diseased tissue, plaque shifting, vessel spasm, dissection with or without intimal flaps, thrombosis, and embolism.
As described in related copending U.S. patent application Ser. No. 08/744022 filed Nov. 4, 1996, now abandoned; Ser. No. 09/007265 filed Jan. 14, 1998; Ser. No. 08/935,383 filed Sep. 23, 1997; and No. 60/088301 filed Jun. 5, 1998; and PCT Patent Application Publication No. WO 99/00835 filed Jan. 14, 1998; systems have been developed for deploying a main stent in a main vessel at the intersection of a main vessel and a branch vessel with a branch stent extending into a branch vessel through a side opening in the main stent.
In a first approach, these systems describe first inserting a first guidewire, then inserting a second guidewire and then inserting main and branch stents over the respective first and second guidewires and into the bifurcation, wherein the second guidewire passes through a side hole in the main stent and into the branch vessel. In a second approach, these systems describe inserting a first guidewire, then inserting an assembly (comprising the main stent and a system for positioning the second guidewire, for example, a dual lumen catheter) over the first guidewire and into the bifurcation. Thereafter, the second guidewire is fed through its positioning system such that the second guidewire passes out through the side opening in the main stent, and into the branch vessel.
Unfortunately, several difficulties exist in the first approach when attempting to first insert separate guidewires into both the main vessel and the secondary vessel before positioning the main stent in the main vessel with a or without a branch stent projecting through a side opening in the main stent into a branch vessel.
Specifically, when attempting to guide two such separate guidewires through the main vessel such that one enters the branch vessel, the two guidewires typically tend to wrap around one another and become entangled. Additionally, time and effort is required to individually position each of the two guidewires one after another.
An additional disadvantage of conventional stents is the difficulty in visualizing the stents during and after deployment, and in general, the fact that they are not readily imaged by low-cost and easy methods, such as x-ray or ultrasound imaging.
The present invention comprises a dual lumen guidewire introducer system for introducing guidewires into main and branch vessels at a bifurcation. The dual lumens of the present guidewire introducer system each have distal openings which are disposed at different locations along the length of the introducer. Specifically, the distal end of the first lumen opening is preferably disposed at the distal end of the introducer, and the distal end of the second lumen opening is preferably disposed at some distance from the distal end of the introducer. As such, the distal end of the first lumen opening is disposed distally to the distal end of the second lumen opening. According, the distal end of the second guidewire protrudes out of the introducer at a location which is proximal to the location at which the distal end of the first guidewire protrudes out of the introducer. A guidewire is received through each of the first and second lumens.
As will be explained, an advantage of the present dual lumen catheter system is that it may be used to position a first guidewire in a main vessel and a second guidewire into a branch vessel such that either: (1) a main stent may be deployed in a main vessel and a branch stent in a branch vessel, with the branch stent being deployed through an opening in the side of the primary stent with the side opening being in registry with the ostium of the branch vessel, or (2) a main stent may be deployed in a main vessel with a side opening in the main stent being positioned in registry with the ostium of the branch vessel. Alternative main and/or branch stent positioning procedures may also be employed after the system of the present invention has positioned the first and second guidewires in the respective main and branch vessels. The present system may be used in conjunction with any of a variety of existing stenting systems, including xe2x80x9ckissingxe2x80x9d or xe2x80x9chuggingxe2x80x9d balloon and stent systems.
It is to be understood that the used of the present invention are not limited to stent placement. Instead, the present system may in fact be used for any surgical application is which it is beneficial to position first and second guidewires into different branches of a vessel bifurcation.
An important advantage of the present dual lumen guidewire introduction catheter system is that it avoids having to separately position first and second guidewires within the respective main and branch vessels one at a time. As such, the potential for the first and second guidewires tangling around one another is avoided. For example, the present system may be used for the deployment of distal protection devices, xe2x80x9ckissingxe2x80x9d balloon techniques, and renal stenting where one wire is positioned proximal to the renal and a second wire is parked in the renal vessel. The first wire is used to either deliver a stent or protection device proximal to the renal and the second wire is used to deliver a stent or other device, for example, an ultrasound system.
Rather, with the present invention, only a single guidewire needs to initially be placed within the main vessel, with the present guidewire introducer system subsequently facilitating positioning of the second guidewire in the branch vessel. Having dual lumens which separate the first and second guidewires, the present guidewire system advantageously prevents tangling of the guidewires as they are inserted into the bifurcation.
In preferred aspects, a radiopaque marker is provided at the distal end opening of the second lumen, such that the location at which the distal end of the second guidewire protrudes out of the introducer can be viewed under fluoroscopy. Optionally, a radiopaque marker may also be provided at the distal end opening of the first lumen, such that the surgeon can determine that he has advanced distally past the bifurcation.
In optional preferred aspects, radiopaque markers are provided on opposite sides of the introducer shaft at a location proximal the distal end of the second lumen. Such radiopaque markers may be advantageously used to assist the surgeon in aligning a side opening in a main stent with the ostium of a branch vessel.
In optional preferred aspects of the invention, a balloon is positioned at the distal end of the guidewire introducer system. Such balloon may be advantageously used to pre-dilate the main vessel of the vessel bifurcation. This is particularly useful when compressing plaque on the vessel walls or otherwise pre-treating the vessel.
The present invention also comprises a method of inserting a main guidewire into a main vessel and a branch guidewire into a branch vessel at an intersection of a main and branch vessel, comprising: (a) advancing a first guidewire through a main vessel such that a distal end of the first guidewire is positioned past (or alternately, proximate to) the intersection of the main and branch vessels; (b) advancing a dual lumen guidewire introducer through the main vessel over the first guidewire, the first guidewire being received within the first lumen of the dual lumen guidewire introducer; (c) positioning the dual lumen guidewire introducer such that the distal end of the first lumen is disposed past the intersection of the main and branch vessels, and such that the distal end of the second lumen is disposed at the intersection of the main and branch vessels; and (d) advancing a second guidewire through the second lumen such that a distal end of the second guidewire passes out of the distal opening of the second lumen and into the branch vessel.
In optional aspects of the preferred method, a balloon positioned at the distal end of the guidewire introducer is inflated to pre-dilate the main vessel. The inflation of the balloon may preferably carried out either before, after or concurrently with, the insertion of the second guidewire into the branch vessel.
In preferred aspects of the method, positioning the dual lumen guidewire introducer such that the distal end of the second lumen is disposed at the intersection of the main and branch vessels comprises viewing a radiopaque marker positioned adjacent to the distal end of the second lumen. Also in preferred aspects of the method, positioning the dual lumen guidewire introducer such that the distal opening of the first lumen is disposed distally past the intersection of the main and branch vessels comprises viewing a radiopaque marker positioned adjacent to the distal end of the second lumen.
In an optional preferred aspect of the present invention, the guidewire introducer is easily removed leaving the first and second guidewires in place in the main and branch vessels. As described in related copending U.S. patent application Ser. No. 08/744,022 filed Nov. 4, 1996, now abandoned; Ser. No. 09/007,265 filed Jan. 14, 1998; Ser. No. 08/935,383 filed Sep. 23, 1997; U.S. Provisional Patent Application No. 60/088,301 filed Jun. 5, 1998; and PCT Patent Application Publication No. WO 99/00835 filed Jan. 14, 1998; first and second catheters may then be advanced over the respective first and second guidewires to position respective main and branch stents.
In further preferred aspects of the present invention, the guidewire introducer is formed of a tear-away material, having longitudinal sections separated by tear-apart seals such that an operator can hold the guidewires while removing the introducer, yet avoid pulling the guidewires out as the introducer is removed.
Further advantages of the present peel away system include the fact that it avoids the need for long exchange length guidewire, since the surgeon is able to access the guidewires at a location much closer to the surface of the patient""s body.
Applications of the present system include the cardiac, coronary, renal, peripheral vascular, gastrointestinal, pulmonary, urinary and neurovascular systems and the brain. Further advantages of the present dual lumen catheter system are that it provides an improved stent delivery apparatus, which may deliver primary and branch stents to: 1) completely cover the bifurcation point of bifurcation vessels; 2) be used to treat lesions in one branch of a bifurcation while preserving access to the other branch for future treatment; 3) allow for differential sizing of the stents in a bifurcated stent apparatus even after a primary stent is implanted; 4) treat bifurcation lesions in a bifurcated vessel where the branch vessel extends from the side of the primary vessel; and 5) be marked with, or at least partly constructed of, material which is imageable by commonly used intraluminal catheterization visualization techniques including but not limited to ultrasound or x-ray.